Ecdysone titers and prothoracic gland activity during the larval-pupal development of Manduca sexta

The titer of ecdysone in whole animal extracts of Manduca sexta was determined by radioimmunoassay during the fifth (last) larval instar, pharate pupal development and pupation. A subtle peak in ecdysone concentration was noted at day 4 (just prior to the onset of the wandering stage) and a second and greater peak at day 8.5 (coincident with pharate pupal development). The titer fluctuations during development were a result of changes in tissue ecdysone and not of alterations in the ecdysone content of the gut. When prothoracic gland secretory activity was analyzed in vitro at the same stages, the most rapid rate of α-ecdysone secretion was shown to occur on day 7 (one day prior to the peak in whole-animal ecdysone concentration). An earlier peak in prothoracic gland activity may occur at day 4–5. Thin layer and gas-liquid chromatographic analyses revealed developmental changes in the ratio of β:α-ecdysone in hemolymph and whole-animal extracts. It is suggested that the steroid-hydroxylating capacity of the insect increases during the instar.     

Increased Acetylcholine Synthesis and Release in Brains of Cats with GM1 Gangliosidosis

Cholinergic processes were measured in motor cortex, hippocampus, and striatum of cats in the terminal stages of GM1 gangliosidosis and compared to those of control cats. The greatest difference observed was elevation in the rate of K+-stimulated release of acetylcholine (ACh) from brain slices prepared from affected cats. The K+-stimulated release of endogenous ACh was increased by 31-43% and of newly synthesized ACh by 19-80% in brain slices from different brain regions. All regions that were examined were affected but the greatest effects occurred in cortex. The rate of synthesis of ACh was elevated in cortical and hippocampal slices. Choline acetyltransferase activity in brain regions of cats with GM1 gangliosidosis was not significantly different from that in controls, whereas high-affinity choline transport in cortical synaptosomes was elevated. Muscarinic receptor binding sites were reduced in the cortex, hippocampus, and striatum of GM1 mutant cats, whereas the apparent affinity was not altered. These results indicate that there are major alterations of cholinergic function in the brains of cats with GM1 gangliosidosis.     

Development of a pharmacophore model for the catecholamine release-inhibitory peptide catestatin: Virtual screening and functional testing identify novel small molecule therapeutics of hypertension

The endogenous catecholamine release-inhibitory peptide catestatin (CST) regulates events leading to hypertension and cardiovascular disease. Earlier we studied the structure of CST by NMR, molecular modeling, and amino acid scanning mutagenesis. That structure has now been exploited for elucidation of interface pharmacophores that mediate binding of CST to its target, with consequent secretory inhibition. Designed pharmacophore models allowed screening of 3D structural domains. Selected compounds were tested on both cultured catecholaminergic cells and an in vivo model of hypertension; in each case, the candidates showed substantial mimicry of native CST actions, with preserved or enhanced potency and specificity. The approach and compounds have thus enabled rational design of novel drug candidates for treatment of hypertension or autonomic dysfunction.     

A survey of modern pollen and vegetation along an altitudinal transect in southern Georgia, Caucasus region

This paper describes the pollen representation of vegetation patterns along an altitudinal transect in the South Caucasus region. Surface sediments from eight small- to medium-sized lakes and wetlands were analysed for modern pollen, and the results analysed numerically using detrended correspondence analysis (DCA) and dichotomised ordination (TWINSPAN). Pollen spectra from the semidesert region have a clear palynological signal characterised by an abundance of Chenopodiaceae. Differentiation of oak forest, upper tree-line and subalpine communities is more difficult: all are dominated by arboreal pollen (AP) types. The authors propose a number of indicator pollen types and pollen threshold values that may assist in detecting tree-line variations and deforestation events in Holocene pollen diagrams.     

cDNA cloning by amplification of circularized first strand cDNAs reveals non-IRE-regulated iron-responsive mRNAs

Currently, the rapid amplification of cDNA ends (RACE) is the most common method for PCR cloning of cDNA. Because RACE uses a gene specific primer and one adaptor primer that is shared by all cDNAs may result in numerous nonspecific products that can hinder the cloning process. Here we report a new method that uses circularized first strand cDNA from mRNA and two gene specific primers to amplify both the 5' and 3' cDNA ends in one reaction. A cDNA band of correct size can be obtained on the first pass in this approach. If the correct size is not obtained on the first pass, amplification of cDNA ends can be repeated until the correct size of the cDNA is obtained. We tested this new method on eight mRNAs that we have previously shown to respond to cellular iron levels. We obtained sequences for six mRNAs that were 43 bp to 1324 bp longer than that reported in GenBank and obtained the same length sequence for the other two mRNAs. RNA folding program shows no iron responsive elements (IRE) on these mRNA. In conclusion, our cloning approach offers a more efficient method for cloning full-length cDNA and it may be used to replace the existing method of 5' end cDNA extension. The data enabled us to exclude the possibility that the expression of these iron responsive genes are regulated by IREs.     

The identification of p-acetamidobenzoate as a folate degradation product in rat urine.

Within 48 h of administration of radiolabelled 10-formylfolate, folic acid and the polyglutamate derivative 10-formylfolate tetraglutamate to the rat, fragmentation products are found in the urine. The major catabolite was identified as p-acetamidobenzoate by chromatography and reverse isotope-dilution analysis.     

On the phytoscreening potential of insect-induced plant galls

Plant and Soil - Tussock microhabitat is a universal phenomenon in wetlands, where soil and plant properties differ from their surrounding lawns. This study aims to investigate the differences of...     

Characterizing the movements and habitat use of two fish species of concern in a regulated ecosystem

Hydrobiologia - In freshwater ecosystems in the northwest United States, the distribution and movements of fish between their essential habitats are particularly impacted by the presence of...     

Oystershell scale: an emerging invasive threat to aspen in the southwestern US

Biological Invasions - Oystershell scale (OSS; Lepidosaphes ulmi) is an emerging invasive insect that poses a serious threat to conservation of quaking aspen (Populus tremuloides) in the...